The term "sleeving" is misleading. The new barrels are full thickness all the way from the muzzle back to the "monobloc", then they line the chambers all the way to the rim cut for the shell rim. Nothing is used from the old set except the "mono bloc", or chamber areas, which may of may not be a true monobloc. The old ribs are used and the old fore end lug is put on the new tubes.
Look at some of the links Drew posted. They show this better than I can explain it.
SRH
Last edited by Stan; 04/29/15 10:30 PM.
